1. Technical Field
The present invention relates to an electrooptic device substrate, an electrooptic device, and an electronic apparatus.
2. Related Art
Known has been an electrooptic device including an electrooptic material (for example, liquid crystal or the like) between an element substrate on which a plurality of pixels and switching elements are provided and a counter substrate arranged so as to oppose the element substrate. As the electrooptic device, a liquid crystal device that is used as a liquid crystal light valve of a projector, and the like can be exemplified.
When intense light from a light source enters the liquid crystal light valve, if semiconductor layers constituting the switching elements are irradiated with the light, a light leakage current is generated and flicker and pixel unevenness occur on a display image. Therefore, for example, employed is a configuration in which data lines located at the upper-layer side of the semiconductor layers and scan lines located at the lower-layer side of the semiconductor layers block the light incident from the upper and lower directions of the semiconductor layers.
In the liquid crystal light valve, an aperture ratio of a pixel region through which light passes is required to be improved. If a light-shielding layer is made narrower in order to improve the aperture ratio, light is easy to be incident on the semiconductor layers obliquely from the sides of the light-shielding layer. In order to avoid this, disclosed is a technique of blocking light incident on the semiconductor layers obliquely in the flowing manner (for example, see JP-A-2008-77030). That is, grooves reaching the scan lines located at the lower-layer side of the semiconductor layers from an insulating layer located at the upper-layer side of the semiconductor layers are provided on regions overlapping with the scan lines at both sides of the semiconductor layers when seen from the above. Further, gate electrodes having a light shielding property are also provided in the grooves.
However, in a process of forming a conductive film serving as the gate electrodes, it is difficult to form the conductive film in the above-mentioned grooves, and portions on which the conductive film is not formed are generated partially in some cases. Moreover, when anneal processing for activating an impurity injected into the semiconductor layers is performed after the gate electrodes are formed, the gate electrodes are exposed at a high temperature. Because of this, an optical density (OD) value of a material constituting the gate electrodes is lowered, resulting in lowering the light shielding property of the gate electrodes. Then, the light incident on the semiconductor layers obliquely is not blocked sufficiently. Due to this, the light leakage current in the switching elements is increased and optical malfunction occurs, resulting in occurrence of flicker and display unevenness. This raises a problem that display quality of the liquid crystal device is lowered.